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The BBO Crystal is an efficient NLO crystal for the second, third and fourth harmonic generation of Nd:YAG lasers, and the best NLO crystal for the fifth harmonic generation at 213 nm. Conversion efficiencies of more than 70% for SHG, 60% for THG and 50% for 4HG, and 200 mW output at 213 nm (5HG) have been obtained, respectively. BBO Crystal has the following.

Advantages of BBO Crystal
Broad phase-matching range from 409.6 nm to 3500 nm 
Wide optical transmission from 190 nm to 3500 nm 
Large effective second-harmonic-generation (SHG) coefficient 
High damage threshold of 10 GW/cm2 for 100 ps pulse-width at 1064 nm 
Wide temperature-bandwidth of about 55℃ 
Good mechinical and physical properties 
Aperture: 2x2 ~ 25x25mm
Lenght: 0.01 - 25mm
Cutting Angle of BBO Crystal q and f: Determined by different kinds of homonic generartion
Phase matching type: Type I or Type II
End Configuration: Plano/Plano or Brewst/Brewst or Specified


Specifications of BBO Crystal
Angle tolerance: Δθ< ± 0.5°; Δφ< ±0.5°
Dimensional Tolerance: (W ± 0.1mm) x (H ± 0.1mm) x (L + 0.2mm/-0.1mm)
Flatness: <λ/8 at 633nm
Surface Quality: 10/5 S/D
Parallelism: < 20 arc seconds
Perpendicularity: < 5 arc minutes
Wavefront Distortion: <λ/8 at 632.8nm
Clear Aperture: Central 95%
Chamfer: 0.15x45°
Coating: * Protective coating is required to prevent polished surfaces from fogging.
* Anti-reflective coating should be considered if low reflectivity is required.

Properties of BBO Crystal:

Crystal Structure trigonal, space group R3c
Cell Parameters a = b = 12.532Ä, c = 12.717Ä, Z = 6
Melting Point 1095 +/-5°C
Transition Temperature 925 +/-5°C
Optical Homogeneity Dn ≈10-6/cm
Mohs Hardness 4.5
Density 3.85 g/cm3
Absorption Coefficient < 0.1%/cm (at 1064 nm)
Hygroscopic Susceptibility low
Resistivity > 1011 ohm-cm
Relative Dielectric Constant εT110: 6.7, εT330: 8.1
Tan δ, < 0.001
Thermal Expansion Coefficients(in the range of 25℃- 900℃) a, 4 x 10-6/K
c, 36 x 10-6/K
Thermal Conductivity ^c, 1.2 W/m/K; ||c, 1.6 W/m/K


Phase-matchable SHG range 205nm-1750nm
NLO coefficients d11 = 5.8 x d36(KDP)
d11 = 0.05 x d11, d22< 0.05 x d11
Electro-Optic Coefficients g11 = 2.7 pm/V, g22, g31< 0.1 g11
Half-Wave Voltage 48 KV (at 1064 nm)
Damage Threshold
at 1.064 mm
at 0.532 mm
5 GW/cm2 (10 ns);
10 GW/cm2 (1.3 ns)1 GW/cm2 (10 ns);
7 GW/cm2 (250 ps)
Transparency Range 189 - 3500 nm
Refractive Indices
at 1.0642 mm
at 0.5321 mm
at 0.2660 mm

ne = 1.5425, no = 1.6551
ne = 1.5555, no = 1.6749
ne = 1.6146, no = 1.7571
Therm-Optic Coefficients dno/dT = - 9.3 x 10-6/℃
dne/dT = -16.6 x 10-6/℃

Sellmeier Equations:
no2(λ) = 2.7359+0.01878/(λ2-0.01822)-0.01354 λ2
ne2(λ) = 2.3753+0.01224/(λ2-0.01667)-0.01516 λ2
BBO optical properties:
Transparence range: 189-3500nm
Second harmonic generation (SHG) range: 410-2400nm
Type I phase matching plane: X-Z plane, φ=0°
Type I phase matching plane: X-Z plane, φ=30°

The crystals with different angle cut for various applications are listed as follows:

1) Harmonic generations of Nd:YAG lasers:
1064nm SHG --> 532nm: 4x4x7mm Type I , θ=22.8°, φ=0°;
1064nm THG --> 355nm: 4x4x7mm Type I, θ=31.3°, φ=0°; Type II q=38.6°, φ=30°
1064nm 4HG --> 266nm: 4x4x7mm Type I, θ=47.6°, φ=0°;
1064nm 5HG --> 213nm: 4x4x7mm Type I, θ=51.1°, φ=0°;
2) OPO and OPA pumped by harmonics of Nd:YAG lasers
532nm Pump --> 680-2600nm: 8x6x12mm Type I, θ=21°, φ=0°;
355nm Pump --> 410-2600nm: 8x6x12mm Type I, θ=30°, φ=0°; Type II, q=37°, φ=30°;
266nm Pump --> 295-2600nm: 8x6x12mm Type I, θ=39°, φ=0°;

3) Frequency doubling of dye lasers
670-530nm SHG --> 335-260nm: 8x4x7mm Type I, θ=40°, φ=0°;
600-440nm SHG --> 300-220nm: 8x4x7mm Type I, θ=55°, φ=0°;
444-410nm SHG --> 222-205nm: 8x4x7mm Type I, θ=80°, φ=0°;

4) Harmonic generations of Ti:Sapphire lasers
700-1000nm SHG --> 350-500nm: 5x5x0.2mm Type I, θ=28°, φ=0°;
700-1000nm THG --> 240-330nm: 5x5x0.2mm Type I, θ=42°, φ=0°;
700-1000nm FHG --> 210-240nm: 5x5x0.2mm Type I, θ=66°, φ=0°;

5) Frequency doubling and tripling of alexandrite lasers
720-800nm SHG --> 360-400nm: 6x4x7mm Type I, θ=31°, φ=0°;
720-800nm THG --> 240-265nm: 6x4x7mm Type I, θ=48°, φ=0°;

6) Intracavity SHG of Ar+ laser with brewster angle cut BBO Crystal
514nm SHG --> 257nm: 4x4x7mm Type I, θ=51°, φ=0°, B-cut;
488nm SHG --> 244nm: 4x4x7mm Type I, θ=55°, φ=0°, B-cut;

Mounting: In order to prevent crystals from damaging or to be easily operated, CryLight provide three kinds of mount of holder to install different dimension crystals. Please contact our sales for more information.


Part No. Size(mm) Type θ φ Coating
BBO001 4x4x7 I 22.8° AR/AR@1064&532nm
BBO002 4x4x7 I 47.6° AR/AR@532&266nm
BBO003 4x4x10 I 22.8° AR/AR@1064&532nm
BBO004 4x4x10 I 47.6° AR/AR@532&266nm
BBO005 5x5x2 I 29.2° AR/AR@800&400nm
BBO006 5x5x1 I 29.2° AR/AR@800&400nm
BBO007 5x5x0.3-0.5 I 29.2° AR/AR@800&400nm
BBO008 5x5x0.1 I 29.2° AR/AR@800&400nm